Operating mechanism for searchlights, guns, and the like



April 22 1924. 1,491,377

. G. K. CALHOUN OPERATING MECHANISM FOR SEARCHLIGHTS, GUNS, AND THE LIKE Filed Jan. 2, 1920 20 Guy K. Cal houfi,

Patented Apr. 22, 1924.

:12: rres GUY K. CALHOUN, OF THE UNITED STATES NAVY, ASSIGNOR T GENERAL ELECTRIC COMPANY, A. COREORATIQN 01'! NEW YORK.

OPERATING MECHANISM FOR, SEARCHLIGHTS, GUNS, AND THE LIKE.

Application filed January 2, 1920. Serial No. 348,845.

mounted for rotation therewith a Search light, gun or other object which is adapted to be moved with reference to the turn-table in a plane at right angles to the plane of movement of the turn-table by a shaft whichv is coaxial with the turn-table.

My invention has a particular application in the control of searchlight projectors and the like, although it will be apparent to those skilled in the art that my invention is by no means limited to such use; Projectors are ordinarily mounted on a turn-' table or other support so as to be rotated to any desired position- It is customary to move the projector in the vertical plane by means of a shaft which is coaxial with the turn-table. Such arrangements have heretofore had the disadvantage that a rotation of the turn-table caused the projector to be 0 simultaneously moved a proportionate distance in the vertical plane.

The object of my invention is to obviate the difficulties heretofore experienced in the operation of devices of this character, and

5 it provides means whereby a movement of the object in either plane does not alter or effect a change in its position in the other plane, and whereby the object may be simultaneously moved. in both planes if desired 49 without the movement in either plane altering or affecting the movement in the other plane. In carrying my invention into effect, I provide a differential gearing arrangement whereby the tendency to move the object in one plane due to the movement of the object in the other plane is automatically compensated for, so that all that the operator need do is to cause the object to be moved to the desired position, whether the movement of the object is in the horizontal or vertical plane or both, without paying any regard whatsoever to the effect which movement in one plane would have in varying the position of the object in the other plane.

For a better understanding of my invention, reference is had to the accompanying drawing wherein I have shown my invention embodied in concrete form for purposes of illustration, and in which Fig. 1 shows a projector and its control arrangement embodying my invention; Fig. 2 is a detail of Fig. 1 showing the arrangement whereby the position of the Searchlight in both the horizontal and vertical plane is varied without the movement of the projector in one plane altering its position in the other plane.

Referring first to Fig. 1, the projector 10 is trunnioned in two supporting arms 11 and 12 which are secured to the rotatable support or turn-table 13 so that a rotation of the turn-table causes the projector to be also rotated. The turn-table 13 is provided on its outer periphery with gear teeth with which the pinion 14 is adapted to mesh. This pin ion 14: is secured to and rotated by means of a shaft 15 which is adapted to be rotated manually, or by means of an electric motor or in any other suitable manner. The projector is adapted to be rotated in elevation by means of a pinion 16 meshing with a gear sector 17 secured to the projector. The pinion 16 is rotated through the bevel gearing shown by means of a bevel gear 18 which I is journaled in the cap 19 secured to the turn-table. The shaft on which the bevel gear 18 is mounted is coaxial with the turntable and is journaled so as to be capable of relative rotation with respectthereto.

Referring to Fig. 2, the bevel gear 18 is driven through a differential gearing rangement by the shaft 20. The bevel gear 18 is also driven in'response to a rotation of the turn-table, as will be later explained. Secured to the end of the shaft 20 is a bevel gear 21 having the same diameter and number of teeth as the bevel gear 22 secured to the shaft on which the bevel gear 18 is mounted. A bevel gear 23 secured to the turn-table and the bevel gear 24 secured to the stationary support on which the turntable is rotated, have each the same diameter and the same number of teeth as the bevel gears 21 and 22. Pinions 25 and 26 cooperate with the gears 21 and 22 to form a bevel gearing arrangement and pinions 27 and 28 cooperate with the bevel gears 23 and 24 to form another difierential arrangement All of these pinions 25, 26, 27 and 28 have the same diameter and the same number of teeth, and each is mounted in a rotatable bracket 29 which is coaxial with the shaft and freely rotatable with respect thereto. Each of the pinions 25, 26, 27 and 28 is freely rotatable with respect to the bracket 29. The turn-table is supported on roller bearings 80.

As thus constructed and arranged, the operation of my invention is as follows: With the projector in the position shown in Fi 1, if it is desired to change its position in the vertical plane, the shaft 20 will be rotated manually, or by means of an electric motor or in any other suitable manner. This will cause the bevel gear 18 to rotate through the bevel gear 21, pinions and 26 and the bevel gear 22. It will be observed that the rotatable bracket 29 is at this time held stationary, since the turntable 13 is stationary and there is no relative rotation between the bevel gears 23 and 2. L so as to permit the pinions 27 and 28 to roll around these gears and thus carry the rotatable bracket with them. The movement of the projector in the vertical plane will have no tendency to vary the position of the turntable or the projector in the horizontal plane.

Assume that the projector has beenmoved to the proper position in the vertical plane, and that it is desired to move it to another position in the horizontal plane. This will be accomplished by rotating the shaft 15 in any suitable manner and thereby rotating the turn-table through the pinion 1d and the gear 13 on the periphery of the turn-table. When this happens, the bevel gear 23 will also be caused to rotate, and with the bevel gear 24 and the bevel gear 21 stationary, the pinions 27 and 28 will be caused to roll around the bevel gear 24 in the same direction as the direction of rotation of the turntable, thereby rotating the bracket 29 in the same direction about the shaft 20. This will cause the pinions 25 and 26 to roll around the bevel gear 21 (now stationary) and cause the bevel gear 22 to be rotated in the same direction and at the same speed as the turntable. The operation will be the same as if the bevel gear 18 were rigidly secured to the turn-table, and by reason of the fact that there is no relative rotation between the bevel gear 18 and the turn-table, the projector will be moved in the horizontal plane without the movement in this plane affecting in any way the position of the projec tor in the vertical plane. It will be apparent that the turn-table may be moved con tinuously in one direction without altering in any way the position of the projector in the vertical plane.

It will be apparent to those skilled in the art that if both the shaft 15 for effecting the horizontal rotation of the turn-table and the shaft 20 for effecting the movement of the projector in elevation are simultaneously rotated, the movement in each plane will be accomplished without in any manner affecting the movement in the other plane. Thus, assuming that the turn-table is being rotated and that it is desired to sin'iultaneously elevate or lower the projector to any desired position, the shaft 20 will be rotated in the proper direction and the bevel gear 18 will be caused to rotate in the same direction as the direction of rotation of the turn-table, slower or in the opposite direction depend ing upon the direction of rotation and the speed of the shaft 20, and the speed of rotation of the turn-table.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the a pparatus shown is only illustrative and that the invention can be'carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is:

The combination with a rotatable support, an object mounted on the same, and means for moving the object in a plane at right angles to the plane of movement of the support comprising a shaft coaxial with the rotatable support, of a double differential gear mechanism, the said mechanism having a gear connected to said shaft, a second shaft coaxial with thesupport, a gear connected to said second shaft, a gear driven by the said support, a stationary gear, and a rotatable member coaxial with the support having gear mechanism for transmitting power from said second shaft to the first mentioned shaft, and for transmitting power from the support to the first mentioned shaft for preventing a movement of the object in one plane due to a movement of the object in the other plane.

In witness whereof, I have hereunto set my hand this second day of January 1920.

GUY K. CALHOUN. 

